I'm helping a buddy of mine troubleshoot an overheating problem with his 97 disco. I'm a Jeep guy, but I don't want my buddy to get rid of his disco.

- Waterpump, t-stat and clutch fan are less than 10 months old.
- proper coolant level, with no noticable drop in the level
- No discernible coolant leaks
- His truck only runs hot with the AC running. As soon as AC is turned off, engine temps cool back down.
- Fan comes on when AC is running - not sure if it's only one or both.

I'm not well-versed on the two electric fans (XJs only have 1). Is one e-fan the 'regular' fan that comes on when the Disco hits a certain temp, and the other e-fan only for when the AC is running?

It looks as though his Disco only runs hot with the extra load on the engine (AC), so I'm leaning towards something like one or more of the fans aren't functioning 100%. I've read on here that the AC fan can seize up.

Thoughts?

 

Check both fans, they should both come on when either the engine is at operating temp or the a/c is on.
How about the mechanical fan?

 

Both of mine come on with the AC.
Mine is a 96 so it should be the same.

 

I'll get him to check that both of the e-fans are running at operating temperature and when the AC is on.

I assume that the e-fan is either working or not? Like, the e-fan won't work 80% of normal operating speed?

 

The clutch fan is less than 10 months old, so I assume it's working properly. What's the testing procedure for that?

 

Both e-fans are supposed to come on as soon as you turn ion the a/c, weather or not the engine is stone cold or boiling over, press the a/c button and both fans come on.

As for checking the clutch fan, with the engine running at temp do you feel air moving behind it?
So with the engine running and at temp stick your hand by the t-stat, do you fell air moving?

 

My buddy took it to a LR place to get the cooling system worked on 11 months ago, which is why it has new t-stat and water pump, etc. They said everything was in working order.

Assuming the fans are in working order, where's the next place to start looking? Perhaps a bad sensor?

 

Back to your fan's, how many are running when the a/c is on, this is important.

 

I'll get him to double check and see which fans are running with the AC running.

thanks for all the help.

 

Alright, so both of the fans are running when the AC is engaged.